Process of preparing anthramid vat dyestuff



United States Patent 3,023,220 PROCESS OF PREPARING ANTHRAMID VAT DYESTUFF Joseph S. Milazzo, Palisades Park, N.J., assignor to Gen-v eral Aniline & Film Corporation, New York, N.Y., a

corporation of Delaware No Drawing. Filed Oct. 22, 1959, Ser. No. 847,879

2 Claims. (Cl. 260-316) This invention relates to an anthamid vat dyestuif and particularly to an improved process of preparing Indanthrene Olive R (yellow shade).

It is known that an olive-gray vat dyestutt can be prepared by the treatment of dibenzoyl-p-p'-diamino-a-eU-dianthramid with concentrated sulfuric acid. The procedure which is more fully disclosed in United States Patent 996,109 involves the heating of 1 part of the said di-anthramid with parts of 66 Be. sulfuric acid with stirring to 30-35 C. until the mass has assumed a bro-wn coloration. 10 parts of a 40% fuming sulfuric acid are then added and the mixture poured on ice. The dye, which separates in the shape of olive-green flakes, is filtered oil and then washed with water.

It is also known that in the preparation of the anthrarnid dye by carbazolation, ring closure is resorted to by treatment with sulfuric acidat low temperatures i.e., below -25 C.; Chemistry of Synthetic Dyes and Pigments by H. A. Lubs, page 464. The low temperatures are employed to prevent hydrolysis of the benzamido groups and to eliminate low yields and low dyeing strength of the olive-gray dyestufi.

I have made the surprising discovery that the anthramid dyestufi can be readily prepared in a much more facile and economical manner by conducting the carbazolation, ring closure, at -25 C. and eliminating the use of 40% fuming sulfuric acid. After the ring closure is complete, indicated by a color change in sulfuric acid from yellow green to golden brown, water is added as the temperature rises to 60-65 C. but not over 80-85 C. to give a microcrystalline product when examined under the microscope. The acid mixture is then precipitated in water and given a sodium bichromate purification. Then, the purified dyestutf is filtered, washed neutral. The dyestuif produced dyes cotton from an alkaline hydrosulfite vat fast olive-gray shade substantially yellower than Indanthrene Olive RAP Dbl pst new; Color Index 1150. This discovery is of great economic significance since the uses of Indanthrene Olive R are numerous, such 'as'in self shades and also in mixed browns which make groups were noticed since high yields, were obtained (about 95% of'theory based on color value). All fast-v ness properties, chlorine, light and wash are excellent. when compared to Ind. Olive RAP Dbl pst new; Color Index 1150.

The following examples will more fully describe the improved process of the present invention. .All parts given are by weight. I

Example I A 1 part of 1,1'-iminobis-(4-benzoylamino anthraquinone) produced by condensing benzoyl chloride and l,l-imidoer ICC C. with '10 parts of sulfuric acid 96%. Stirring at 20- 25 C. was continued for 1 hour or until a golden brown coloration was observed. When carbazolation was complete, as indicated by a color change from yellow green to golden brown, 1.3-1.6 parts of water were added as the temperature rose to 6065 C. but not over 85 C. After the water addition was made, the mixture was stirred at 60-65 C. for 2 hours. The mass was then poured into 36-40 parts of water to precipitate the dyestufi'. The mixture was heated to 60- C. and purified by adding 0.25 part of sodium bichromate. It is then filtered and washed neutral with water. The dyestutf obtained dyes cotton an olive shade with a yellow cast (substantial) when compared to Indanthrene Olive RAP Dbl Pst new; Color Index 1150.

Example II 1 part of l,l-iminobis-(4-benzoylamino anthraquinone) produced by condensing benzoyl chloride and 1, 1'-irninobis (4-arninoanthraquinrne) was stirred at 20"- 25 C. with 10 parts of sulfuric acid 96%. Stirring at 20-25 C. was continued for 1 hour or until a golden brown coloration was observed. When the carbazolation was complete, as indicated by a color change from yellow green to golden brown, 1.3-1.6 parts of Water were added below 20 C. After the water addition, the mixture was heated to 60-65 but not over 80- 85 C. and held for 2 hours. The mass was then poured into 36-40 parts of water to precipitate the dyestufl. The mixture was heated to 60-85 C. and purified by adding 0.25 part of sodium bichromate. It was then filtered and washed neutral with water. The dyestuff obtained dyes cotton an olive shade with a yellow cast (substantial) when compared to Indanthrene Olive RAP Dbl pst new, Color Index 1150.

Example 111 1 part of 1,1'-iminobis-(4-benzoylamino anthraquinone) produced by :cndensing benzoyl chloride and 1,1- iminobis (4-aminoanthraquinone) was stirred at 20- 25 C. with 10 parts of sulfuric acid 96%. Stirring 20- 25 C. was continued for 1 hour or until a golden brown coloration was observed. When the carbazolation was complete, indicated by a color change from yellow green to golden brown, 1.3-1.6 parts of water were added below 20 C. After the water addition, the mixture was heated to 35 -65 C. and 0.14 part of manganese dioxide added. The mixture was stirred at 35-65 C. for 2-4 hours. The resulting mass-was poured into 36-40 parts of water to precipitate the dyestuff. The mixture was heated to 60-85 ;C. and purified byfadding 0.25 part of sodium bichromate. It was then filtered and washed neutral with water. The dyestufi obtained dyes cotton an olive shade with a yellow cast (substantial) when compared to Ind. Olive RAP Dbl pst new; Color Index 1150.

'bichrornate to purify the same followed byisolation of his (4-aminoanthraquinone) was stirred at 20-25 l. the purified vat dyestutf by filtration.

2. The process of preparing 1,2,7,8-diphthaloy1-3,6-di- References Cited in the file of this patent (benzoylamino) carbazole vat dyestufi which consists UNITED STATES PATENTS treating 1 part by weight of 1,l'-iminobis-(4-benzoylaminoanthraquinone) with 10 parts by weight of 96% sulfur- 1885172 Baumann 1932 ie acid at about room temperature for a period of time to 5 2,278,973 Cm 1942 yield a golden-brown coloration, adding from 1.3 to 1.6 FOREIGN PATENTS parts by weight of water, maintaining the temperature be- 5 5 5 Great Britain May 12, 1939 tween 60-85 C., pouring "the sulfuric acid mixture into water and adding 0.25 part by weight of sodium bichro- OTHER {{EFERENCES mate, and isolating the said dyestuff by filtration. 10 Veflkataramani synthetlc Dyes, P- 900 

1. THE PROCESS OF PREPARING 1,2,7,8-DIPHTHALOYL-3,6-DI(BENZOYLAMINO)-CARBAZOLE VAT DYESTUFF WHICH CONSISTS TREATING 1,1''-IMINOBIS - (4-BENZOYLAMINOANTHRAQUINONE) WITH 96% SULFURIC ACID AT ABOUT ROOM TEMPERATURE FOR A PERIOD OF TIME TO YIELD A GOLDEN-BROWN COLORATION, ADDING SUFFICIENT WATER AS THE TEMPERATURE RISES TO BETWEEN 6085*C. TO YIELD A MICROCRYSTALLINE PRODUCT, PRECIPITATING THE SULFURIC ACID MIXTURE IN WATER AND ADDING SODIUM BICHROMATE TO PURIFY THE SAME FOLLOWED BY ISOLATION OF THE PURIFIED VAT DYESTUFF BY FILTRATION. 